Oracle

Oracle Interview Questions – Part 11

Q.Can you store objects in library?

Referencing allows you to create objects that inherit their functionality and appearance from other objects. Referencing an object is similar to copying an object, except that the resulting reference object maintains a link to its source object. A reference object automatically inherits any changes that have been made to the source object when you open or regenerate the module that contains the reference object.

Q.What is SECURE property?

– Hides characters that the operator types into the text item. This setting is typically used for password protection.

Q.If you have property class attached to an item and you have same trigger written for the item . Which will fire first?

Item level trigger fires , If item level trigger fires, property level trigger won’t fire. Triggers at the lowest level are always given the first preference. The item level trigger fires first and then the block and then the Form level trigger.

Q.What are the types of triggers and how the sequence of firing in text item?
Triggers can be classified as Key Triggers, Mouse Triggers ,Navigational Triggers.
Key Triggers :: Key Triggers are fired as a result of Key action.e.g :: Key-next-field, Key-up,Key-Down
Mouse Triggers :: Mouse Triggers are fired as a result of the mouse navigation.e.g. When-mouse-button-presed,when-mouse-doubleclicked,etc
Navigational Triggers :: These Triggers are fired as a result of Navigation. E.g. : Post-Text-item,Pre-text-item.
We also have event triggers like when ?new-form-instance and when-new-block-instance.
We cannot call restricted procedures like go_to(?my_block.first_item?) in the Navigational triggers
But can use them in the Key-next-item.
The Difference between Key-next and Post-Text is an very important question. The key-next is fired as a result of the key action while the post text is fired as a result of the mouse movement. Key next will not fire unless there is a key event. The sequence of firing in a text item are as follows ::
a) pre – text
b) when new item
c) key-next
d) when validate
e) post text

Q.Can you store pictures in database? How?

Yes , in long Raw datatype.

Q.What are record groups ? Can record groups created at run-time?

A record group is an internal Oracle Forms data structure that has a column/row framework similar to a database table. However, unlike database tables, record groups are separate objects that belong to the form module in which they are defined. A record group can have an unlimited number of columns of type CHAR, LONG, NUMBER, or DATE provided that the total number of columns does not exceed 64K. Record group column names cannot exceed 30 characters.
Programmatically, record groups can be used whenever the functionality offered by a two-dimensional array of multiple data types is desirable.
TYPES OF RECORD GROUP:
Query Record Group A query record group is a record group that has an associated SELECT statement. The columns in a query record group derive their default names, data types, and lengths from the database columns referenced in the SELECT statement. The records in a query record group are the rows retrieved by the query associated with that record group.
Non-query Record Group A non-query record group is a group that does not have an associated query, but whose structure and values can be modified programmatically at runtime.
Static Record Group A static record group is not associated with a query; rather, you define its structure and row values at design time, and they remain fixed at runtime.

Q.Can you issue DDL in forms?

yes, but you have to use FORMS_DDL.
Referencing allows you to create objects that inherit their functionality and appearance from other objects. Referencing an object is similar to copying an object, except that the resulting reference object maintains a link to its source object. A reference object automatically inherits any changes that have been made to the source object when you open or regenerate the module that contains the reference object. Any string expression up to 32K:
– a literal
– an expression or a variable representing the text of a block of dynamically created PL/SQL code
– a DML statement or
– a DDL statement
Restrictions:
The statement you pass to FORMS_DDL may not contain bind variable references in the string, but the values of bind variables can be concatenated into the string before passing the result to FORMS_DDL.
Q.What is ALERT?

An ALERT is a modal window that displays a message notifying operator of some application condition.

Q.What is FORMS_MDI_WINDOW?
forms run inside the MDI application window. This property is useful for calling a form from another one.

Q.Can a button have icon and label at the same time?
-NO

Q.What is mouse navigate property of button?

When Mouse Navigate is True (the default), Oracle Forms performs standard navigation to move the focus to the item when the operator activates the item with the mouse.
When Mouse Navigate is set to False, Oracle Forms does not perform navigation (and the resulting validation) to move to the item when an operator activates the item with the mouse.

Q.What are timers ? when when-timer-expired does not fire?

The When-Timer-Expired trigger can not fire during trigger, navigation, or transaction processing.

Q.What are user-exits?

It invokes 3GL programs.

Q.What are property classes ? Can property classes have trigger?

Property class inheritance is a powerful feature that allows you to quickly define objects that conform to your own interface and functionality standards. Property classes also allow you to make global changes to applications quickly. By simply changing the definition of a property class, you can change the definition of all objects that inherit properties from that class.
Yes . All type of triggers .

Q.Can object group have a block?
Yes , object group can have block as well as program units.

Q.Can you pass values to-and-fro from foreign function? how?

Yes . You obtain a return value from a foreign function by assigning the return value to an Oracle Forms variable or item. Make sure that the Oracle Forms variable or item is the same data type as the return value from the foreign function.
After assigning an Oracle Forms variable or item value to a PL/SQL variable, pass the PL/SQL variable as a parameter value in the PL/SQL interface of the foreign function. The PL/SQL variable that is passed as a parameter must be a valid PL/SQL data type; it must also be the appropriate parameter type as defined in the PL/SQL interface.

Q.How many types of canvases are there?
There are 2 types of canvases called as Content and Stack Canvas. Content canvas is the default and the one that is used mostly for giving the base effect. Its like a plate on which we add items and stacked canvas is used for giving 3 dimensional effect.

Q.Does user exits supports DLL on MSWINDOWS ?

YES .
Q.What is path setting for DLL?

Make sure you include the name of the DLL in the FORMS45_USEREXIT variable of the ORACLE.INI file, or rename the DLL to F45XTB.DLL. If you rename the DLL to F45XTB.DLL, replace the existing F45XTB.DLL in the ORAWINBIN directory with the new F45XTB.DLL.

Q.What is IAPXTB structure?

The entries of Pro * C and user exits and the form which simulate the proc or user_exit are stored in IAPXTB table in d/b.
Q.What is OLE automation?

OLE automation allows an OLE server application to expose a set of commands and functions that can be invoked from an OLE container application. OLE automation provides a way for an OLE container application to use the features of an OLE server application to manipulate an OLE object from the OLE container environment. (FORMS_OLE)

Q.What is precompiler?

It is similar to C precompiler directives.

Q.What are key-mode and locking mode properties? level?

Key Mode : Specifies how oracle forms uniquely identifies rows in the database.This is property includes for application that will run against NON-ORACLE datasources .
Key setting unique (default.)
dateable
n-updateable.
Locking mode :
Specifies when Oracle Forms should attempt to obtain database locks on rows that correspond to queried records in the form. a) immediate b) delayed

Q.How is mapping of name of DLL and function done?

The dll can be created using the Visual C++ / Visual Basic Tools and then the dll is put in the path that is defined the registry.

Q.What is savepoint mode and cursor mode properties ? level?
Specifies whether Oracle Forms should issue savepoints during a session. This property is included primarily for applications that will run against non-ORACLE data sources. For applications that will run against ORACLE, use the default setting.
Cursor mode – define cursor state across transaction Open/close.

Q.Can you connect to non – oracle data source?

Yes.

Q.What does invoke built-in do?
This procedure invokes a method.
Syntax:
PROCEDURE OLE2.INVOKE
(object obj_type,
method VARCHAR2,
list list_type := 0);
Parameters:
object Is an OLE2 Automation Object.
method Is a method (procedure) of the OLE2 object.
list Is the name of an argument list assigned to the OLE2.CREATE_ARGLIST function.